Spoke too soon. As soon as i fully emulated my previous file (which crashed windows), i got the same problem. The song is White Xmas, which is 32 bars long. My system is a PC with 64gb of memory. It is very stable everywhere else and is the latest win11 build.
I believe I might have identified the problem. Because I am using this file for practice, I set the number of repeats to 40. Band in a box can't cope with this here. It did before, but now it cannot do this and my whole system crashes. I have currently set up the number of repeats to 10 and it is working.

I share the link to the working file here, if anyone cares to check it out, try changing the number of repeats to 40 and see if it crashes:

https://1drv.ms/u/c/4aebef484af7e02e/IQBOCK1JFA9eQ5UK2raskWBxAWpoDws4hFKlbfUM2va_Q9k?e=uEzgLc


Thank you all

Z


Win 11 64, Asus Rog Strix z390 mobo, 64 gig RAM, 8700k